Surface Engineering Approach for Enhanced Filler Dispersion and Hysteresis Reduction in Silica/Carbon Black Rubber Compounds

Energy efficient tires have been the focus of the tire industry for the past few decades due to the high fuel prices and more environmental regulations. Different research approaches have been proposed to achieve energy efficient tires, though hysteresis reduction in rubber compounds. One way to achieve better hysteresis properties is by improving the interactions between the filler and rubber matrix. This is done by introducing coupling agents, which act as an intermediate material creating physical or chemical linkages between the two domains.

This study investigates the role of novel Poly(butadiene-graft-pentafluorostyrene-co-trialkoxy(4-vinylphenethyl)silane) [PB-g-P(PFS-co-StSi(OR)3)] as a physical and chemical coupling agent for carbon black (CB) and silica, respectively, in a Butadiene/Styrene Butadiene rubber (BR/SBR) compounds. PFS domains in PB-g-P(PFS-co-StSi(OR)3) are utilized to provide physical bonding with CB, providing an electron-deficient π-ring system that can couple with electron-rich graphitic content of carbon black via arene-perfluoroarene interactions; whereas, StSi(OR)3 domains are utilized to provide chemical bonding by utilizing different alkoxy groups which hydrolyze and/or undergo condensation with the surface SiOH on the silica filler to form covalent siloxane (Si-O-Si) linkages, alkoxy groups being examined are triethoxy-, tripropoxy- and dodecyloxy(diethoxy)-. This coupling leads to increased interactions between the filler and the rubber matrix with PB as the backbone having better affinity for BR and SBR in the rubber compound. The arene-perfluoroarene interactions have been confirmed by zeta potential measurements. Coupling agent and silica interaction are being studied, as well as, compound physical and viscoelastic properties.